This invention generally relates to a stamping die check assembly, and specifically to a die check assembly for checking clearances between an end tool of a workpiece transfer system and a stamping die.
Conventional stamping operations include a series of stamping dies arranged such that a work piece is moved from one stamping die to another until a desired shape is obtained. Stamping operations are often employed for high volume applications such as are required in the automotive industry. At one time, stamping die operations employed human operators to transfer work pieces, between stamping dies. Current stamping operations utilize custom designed and assembled workpiece transfer systems.
Typically, a workpiece transfer system comprises an arm mounted to a shuttle. The shuttle moves between two stamping dies. An end tool disposed on the arm engages the workpiece. The end tool can include a gripper that clamps onto the workpiece or a passive holder known in the art as a “shovel.” The shovel corresponds to a feature on the workpiece to hold the workpiece during movement between stamping dies.
Typically, each stamping die includes an upper and lower part. The upper part lifts away from the lower part to allow removal of the workpiece. Operation of the workpiece transfer system begins with the end tool in a retracted position. The arm advances toward the stamping die from the retracted position as the upper stamping die begins to lift from the lower die. Movement of the transfer system corresponds with movement and the cycle time of the stamping die. It is desirable to reduce the cycle time in order to speed production and increase efficiency. For this reason, the movement of the workpiece transfer system is optimized to begin movement as the stamping die begins to open.
Movement of the end tool begins even before the upper die has fully cleared the lower die. Precious time would be wasted if the end tool remained stationary until the upper die was completely clear. For this reason, movement between the upper die and the end tool is carefully orchestrated to achieve an optimal cycle time. As the upper stamping die lifts from the lower stamping die, the end tool is advanced toward the lower die. The end tool proceeds into the stamping die at a speed relative to movement of an upper die section such that the end tool reaches into the lower die at substantially the instant the end tool clears the upper die.
Much effort is taken to assure that movements between the stamping die and the transfer system are properly synchronized. However, in many instances, different vendors build the stamping line and the transfer line. Therefore, often the first time that the transfer system and the stamping die line are operated together is during a production part approval run. At such a late point of process development, errors or unforeseen obstructions can result in costly delays and repairs.
Accordingly, it is desirable to design and develop a method and device for checking the relationship between a transfer system and a die to confirm a process design and detect possible interference between the transfer tooling and a stamping die.